package com.whynot.frame.auth.jwt.filter;

import com.whynot.frame.auth.jwt.token.JWTToken;
import com.whynot.frame.auth.jwt.utils.JWTUtil;
import com.whynot.frame.auth.shiro.cache.AuthCache;
import com.whynot.frame.basic.common.model.ErrorCode;
import com.whynot.frame.basic.util.RedirectUtil;
import com.whynot.frame.basic.util.SpringUtil;
import com.whynot.frame.basic.util.StringUtils;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authz.AuthorizationException;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


/**
 * 描述: 鉴权的jwt过滤器:
 * 作者: chenyao
 * 日期: 2018-06-30.
 * 项目名称: whynot-boot-shiro-jwt-server
 * 版本: 1.0.0
 * JDK: since 1.8
 */
public class JWTFilter extends BasicHttpAuthenticationFilter {

    private Logger LOGGER = LoggerFactory.getLogger(this.getClass());

    /* *//**
     * 判断用户是否想要登入。
     * 检测header里面是否包含Authorization字段即可
     * @param request
     * @param response
     * @return
     *//*
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest req = (HttpServletRequest) request;
        String authorization = req.getHeader("Authorization");
        String requestUrl = req.getServletPath();

        Boolean flag = true;
        Subject subject = SecurityUtils.getSubject();
        if(subject.isAuthenticated()){
            try {
                subject.checkPermission(req.getPathInfo());
            }catch (AuthorizationException e){
                flag = false;
                //throw new AuthorizationException("没有权限");
            }
        }else{
            flag = false;
            //将非法请求跳转到 /401
            //RedirectUtil.toResponse(request, response,"401");
            //throw new UnauthorizedException("没有认证");
        }
        return flag;
        //return authorization != null && requestUrl.equals("/login");
    }*/

    /**
     * 去登录
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String authorization = httpServletRequest.getHeader("Authorization");

        //控制注销，有Jwt没有修改的功能（没法删除/修改失效时间）。所以通过Redis判断
        if(StringUtils.isNotEmpty(authorization) && StringUtils.isEmpty(SpringUtil.getBean(AuthCache.class).getUser(JWTUtil.getUsername(authorization)))){
            throw new AuthenticationException("未认证");
        }

        JWTToken token = new JWTToken(authorization);
        // 提交给realm进行登入，如果错误他会抛出异常并被捕获
        getSubject(request, response).login(token);
        // 如果没有抛出异常则代表登入成功，返回true
        //saveUserToRedis(token);
        return true;
    }

    /**
     * 这里我们详细说明下为什么最终返回的都是true，即允许访问
     * 例如我们提供一个地址 GET /article
     * 登入用户和游客看到的内容是不同的
     * 如果在这里返回了false，请求会被直接拦截，用户看不到任何东西
     * 所以我们在这里返回true，Controller中可以通过 subject.isAuthenticated() 来判断用户是否登入
     * 如果有些资源只有登入用户才能访问，我们只需要在方法上面加上 @RequiresAuthentication 注解即可
     * 但是这样做有一个缺点，就是不能够对GET,POST等请求进行分别过滤鉴权(因为我们重写了官方的方法)，但实际上对应用影响不大
     * @param request
     * @param response
     * @param mappedValue
     * @return
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        try {
            executeLogin(request, response);
        } catch (AuthorizationException e) {
            //将授权的非法请求跳转到 /403
            RedirectUtil.toResponse(request, response,ErrorCode.ERR_UN_AUTH);
            return false;
        } catch (AuthenticationException ae) {
            //将认证的非法请求跳转到 /401
            RedirectUtil.toResponse(request, response, ErrorCode.ERR_UN_TOKEN);
            return false;
        }catch (Exception e){
            LOGGER.error(e.getMessage());
            RedirectUtil.toResponse(request, response,ErrorCode.ERR_SYSERROR);
        }
        return true;
    }
   /* @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response, Object mappedValue) throws Exception {
        HttpServletRequest req = (HttpServletRequest) request;
        Boolean flag = true;
        Subject subject = SecurityUtils.getSubject();
        if(subject.isAuthenticated()){
            try {
                subject.checkPermission(req.getPathInfo());
            }catch (AuthorizationException e){
                //flag = false;
                throw new AuthorizationException("没有权限");
            }
        }else{
            //flag = false;
            //将非法请求跳转到 /401
            //RedirectUtil.toResponse(request, response,"401");
            throw new UnauthorizedException("没有认证");
        }
        return flag;
    }*/

    /**
     * 前置拦截，对跨域提供支持
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }
}
